A Novel Chemical Profile of a Selective In Vitro Cholinergic Essential Oil from (Kunth) Govaerts (Lamiaceae), a Native Andean Species of Ecuador.

A novel chemical profile essential oil, distilled from the aerial parts of (Kunth) Govaerts (Lamiaceae), was analysed by Gas Chromatography-Mass Spectrometry (GC-MS, qualitative analysis) and Gas Chromatography with Flame Ionization Detector (GC-FID, quantitative analysis), with both polar and non-polar stationary phase columns. The chemical composition mostly consisted of sesquiterpenes and sesquiterpenoids (>70%), the main ones being ()--caryophyllene (17.8%), -copaene (10.5%), -bourbonene (9.9%), -cadinene (6.6%), -cadina-1(6),4-diene (6.4%) and germacrene D (4.9%), with the non-polar column. The essential oil was then submitted to enantioselective GC analysis, with a diethyl--butyldimethylsilyl--cyclodextrin diluted in PS-086 chiral selector, resulting in the following enantiomeric excesses for the chiral components: (1,5)-(-)--thujene (67.8%), (1,5)-(+)--pinene (85.5%), (1,5)-(-)--pinene (90.0%), (1,5)-(-)-sabinene (12.3%), ()-(-)-limonene (88.1%), ()-(+)-linalool (32.7%), ()-(-)-terpinen-4-ol (9.3%), ()-(-)--terpineol (71.2%) and ()-(-)-germacrene D (89.0%). The inhibition activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) of essential oil was then tested, resulting in selective activity against BChE with an IC value of 31.3 ± 3.0 μg/mL (positive control: donepezil, IC = 3.6 μg/mL).